Abstract: This study aimed to investigate the role of rotted peanut straw in alleviating the toxic effect of cadmium on peanuts. We carried out a pot culture experiment with a high cadmium accumulation strain Fu 17-N-176 and a low cadmium accumulation cultivar Fuhua 26. Different amounts of rotted peanut straw (0, 2.5, 5.0, 7.5 g·kg^-1 soil) were applied under different cadmium levels (0, 1.0, 2.0 mg·kg^-1 soil) to assess their impacts on peanut growth, physiological characteristics, and kernel cadmium content. The results showed that application of rotted peanut straw enhanced peanut growth under cadmium stress. Compared to the no-straw treatment, application of rotted peanut straw increased main stem height, lateral branch length, and pod weight by 66.9%, 36.6%, and 44.5%, respectively. Moreover, application of rotted peanut straw positively influenced the physiological characteristics of peanuts under cadmium stress. Compared to the no-straw treatment, application of rotted peanut straw increased SPAD value, net photosynthetic rate, and peroxidase activity by 48.3%, 67.6%, and 131.9%, respectively, while decreased the content of malondialdehyde by 25.6%. In terms of cadmium accumulation, application of rotted peanut straw decreased cadmium content in peanut kernels by 51.3%. In soils with cadmium levels of 1.0 and 2.0 mg·kg^-1, application of 7.5 g·kg^-1 of rotted peanut straw demonstrated positive outcomes for peanuts, and the cadmium content in peanut kernels met the national standards of China. This would be the appropriate application amount of rotted peanut straw for cadmium-contaminated soil with these two cadmium levels. Compared to Fu 17-N-176, Fuhua 26 exhibited stronger resistance to cadmium stress. The effect of applying rotted peanut straw to alleviate cadmium stress in Fuhua 26 was better. Therefore, applying rotted peanut straw and selecting low cadmium accumulation peanut cultivars can alleviate the toxic effect of cadmium on peanuts in cadmium-contaminated soil.

Key words: peanut, cadmium stress, rotted peanut straw, growth characteristics, physiological characteristics, cadmium content in peanut kernel